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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_000_007_547">&nbsp;</a>NAME</h4><blockquote>
mbsrtowcs - convert a character string to a wide-character string
(restartable)
</blockquote><h4><a name = "tag_000_007_548">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="wchar.h.html">wchar.h</a>&gt;

size_t mbsrtowcs(wchar_t *<i>dst</i>, const char **<i>src</i>, size_t <i>len</i>,
    mbstate_t *<i>ps</i>);
</code>
</pre>
</blockquote><h4><a name = "tag_000_007_549">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>mbsrtowcs()</i>
function converts a sequence of characters, beginning in the
conversion state described by the object pointed to by
<i>ps</i>,
from the array indirectly pointed to by
<i>src</i>
into a sequence of corresponding wide-characters.  If
<i>dst</i>
is not a null pointer, the converted characters are stored into the
array pointed to by 
<i>dst</i>.
Conversion continues up to and including a terminating null character,
which is also stored.  Conversion stops early in either of the
following cases:
<ul>
<p>
<li>
When a sequence of bytes is encountered that does not form a valid
character.
<p>
<li>
When
<i>len</i>
codes have been stored into the array pointed to by
<i>dst</i>
(and 
<i>dst</i>
is not a null pointer).
<p>
</ul>
<p>
Each conversion takes place as if by a call to the
<i><a href="mbrtowc.html">mbrtowc()</a></i>
function.
<p>
If
<i>dst</i>
is not a null pointer, the pointer object pointed to by
<i>src</i>
is assigned either a null pointer (if conversion stopped due to
reaching a terminating null character) or the address just past the
last character converted (if any).  If conversion stopped
due to reaching a terminating null character, and if
<i>dst</i>
is not a null pointer, the resulting state described is the initial
conversion state.
<p>
If
<i>ps</i>
is a null pointer, the
<i>mbsrtowcs()</i>
function uses its own internal
<b>mbstate_t</b>
object, which is initialised at program startup to the initial
conversion state.  Otherwise, the 
<b>mbstate_t</b>
object pointed to by
<i>ps</i>
is used to completely describe the current conversion state of the
associated character sequence.
The implementation will behave as if no function defined in this
specification calls
<i>mbsrtowcs()</i>.
<p>
The behaviour of this function is affected by the LC_CTYPE category of
the current locale.  
</blockquote><h4><a name = "tag_000_007_550">&nbsp;</a>RETURN VALUE</h4><blockquote>
If the input conversion encounters a sequence of bytes that do not
form a valid character, an encoding error occurs.  In this
case, the
<i>mbsrtowcs()</i>
function stores the value of the macro EILSEQ in
<i>errno</i>
and returns
<b>(size_t)-1)</b>;
the conversion state is undefined.  Otherwise, it returns the number
of characters successfully converted, not including the
terminating null (if any).
</blockquote><h4><a name = "tag_000_007_551">&nbsp;</a>ERRORS</h4><blockquote>
The
<i>mbsrtowcs()</i>
function may fail if:
<dl compact>

<dt>[EINVAL]<dd>
<i>ps</i>
points to an object that contains an invalid conversion state.

<dt>[EILSEQ]<dd>
Invalid character sequence is detected.

</dl>
</blockquote><h4><a name = "tag_000_007_552">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_553">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_554">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_007_555">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="mbsinit.html">mbsinit()</a></i>,
<i><a href="mbrtowc.html">mbrtowc()</a></i>,
<i><a href="wchar.h.html">&lt;wchar.h&gt;</a></i>.
</blockquote><h4>DERIVATION</h4><blockquote>
Derived from the ISO/IEC 9899:1990/Amendment 1:1995 (E).
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UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
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